1. Field of the Invention
This invention relates to a tangle-preventive mechanism in a three contact pieces type contact suited to be used for a socket such as a PGA type IC.
2. Brief Description of the Drawings
The PGA type IC has a plurality of lead pins projecting downwardly from a lower surface of a thin IC body. Widely used as contacts on the socket side to be contacted with such lead pins are three contact pieces type contacts as typically disclosed by Japanese Patent Publication No. 75417/1994.
Each contact has a first contact piece and a second contact piece disposed opposite to each other, and a third contact piece disposed between the first and second contact pieces at one side thereof. The lead pin is inserted between the first and second contact pieces from the other side. By laterally moving the lead pin towards the third contact pin from the insert position, the pin is resiliently clamped between the first and second contact pieces with one side of the lead pin allowed to contact the third contact piece. The third contact piece acts as means for increasing a contact surface. In addition, the third contact piece serves to prevent the lead pin from overly laterally moving and help the first and second contact pieces clamp the lead pin.
However, the above contact has the following shortcomings. Since the first, second and third contact pieces are arranged in a generally U-shaped construction in plan view, a slits is formed between the first contact piece and the third contact piece and a slits is formed between the second contact piece and the third contact piece, and component parts of other contacts tend to enter the slits. Particularly, when male terminals of other contacts to be connected to a wiring board enter the slits, tangling can occur and the male terminals can be deformed. This is apparently inconvenient when the contact is automatically implanted in a socket board. As a consequence, yield of the contact itself or the socket with the contact implanted therein is degraded.
The present invention has been accomplished in view of the above situation.